1. Field of the Invention
The present invention relates generally to a video signal digital processing device, an information storage medium for video signal digital processing, and a video signal digital processing method, and more specifically, to an apparatus, an information storage medium and a method for performing image processing using image data obtained by digitally processing a color video signal and accepting the digitally processed color video signal in simple construction or the simple procedure for processing.
2. Description of the Background Art
As a video signal digital processing device for digitally accepting a color video signal to perform storage processing, a circuit as shown in FIG. 11 has been conventionally known. The video signal digital processing device comprises a synchronous separating circuit 1, a sub-carrier generating circuit 2, a luminance/chroma separating circuit 3, a phase shifting circuit 4, color difference demodulating circuits 5r, 5g, and 5b, adding circuits 6r, 6g, and 6b, analog-to-digital (A/D) converters 7r, 7g, and 7b for respectively making analog-to-digital (A/D) conversion for R, G, and B signals representing the three primary colors, i.e., red (R), green (G), and blue (B), and an image processing system 8 containing an image memory.
The synchronous separating circuit 1 separates, when a color video signal (a so-called composite signal or composite video signal) is fed thereto, the color video signal into three signals, i.e., a composite synchronizing signal, a burst flag (included in a color burst signal), and a luminance/chroma (Y/C) signal, and directly feeds the composite synchronizing signal to the image processing system 8, feeds the burst flag to the sub-carrier generating circuit, and feeds the luminance/chroma signal to the luminance/chroma separating circuit 3. The luminance/chroma separating circuit 3 feeds a chroma signal (C) to the color difference demodulating circuits 5r, 5g, and 5b, and feeds a luminance (Y) signal to the adding circuits 6r, 6g, and 6b. The sub-carrier generating circuit generates a sub-carrier signal (i.e., a burst phase signal) on the basis of the burst flag, and feeds the sub-carrier signal to the phase shifting circuit 4. The phase shifting circuit 4 feeds, on the basis of the burst phase signal, a phase signal which is delayed by 90 degrees from the color burst signal to the color difference demodulating circuit 5r, feeds a phase signal which is delayed by 235.8 degrees from the color burst signal to the color difference demodulating circuit 5g, and further feeds a phase signal which is delayed by 180 degrees from the color burst signal to the color difference demodulating circuit 5b. The color difference demodulating circuits 5r, 5g, and 5b respectively generate color difference signals R-Y, G-Y, and B-Y on the basis of the C signal and the phase shifting signal, and feed the signals to the corresponding adding circuits 6r, 6g, and 6b. The adding circuits 6r, 6g, and 6b respectively add the luminance (Y) signal to the color difference signals R-Y, G-Y, and B-Y, to generate the R signal, the G signal, and the B signal, and feed the signals to the corresponding A/D converters 7r, 7g, and 7b. The A/D converters 7r, 7g, and 7b respectively make A/D conversion for the R signal, the G signal, and the B signal, to generate digital values (color data) corresponding to the color signals, feed the digital values to the image processing system 8, and respectively store the digital values in the image memory (or a frame buffer memory) contained in the image processing system 8 for the R signal, the G signal, and the B signal.
In the prior art shown in FIG. 11, the luminance/chroma separating circuit 3, the phase shifting circuit 4, the color difference demodulating circuits 5r, 5g, and 5b are respectively constituted by analog circuits, and three series of A/D converters 7r, 7g, and 7b are provided, so that the circuit arrangement of the video signal digital processing device becomes significantly complicated, and the cost thereof is high. Therefore, the conventional video signal digital processing device cannot be sold at a price which can spread in general homes so that it is rather suitable for a so-called maniac. An analog circuit portion cannot be digitally processed, so that program (or software) processing is difficult to perform.
Therefore, an object of the present invention is to provide a video signal digital processing device, an information storage medium for video signal digital processing, and a video signal digital processing method, in which a color video signal can be accepted after being converted into a data format which is easy to digitally process in simple and low-cost construction.
The present invention has the following features in order to attain the above-mentioned object.
A first aspect of the present invention is directed to a video signal digital processing device for digitally processing an analog color video signal and feeding the digitally processed analog color video signal to a display device, which comprises:
an analog-to-digital conversion portion for converting the analog color video signal into a digital video signal;
a first temporary storage portion for storing digital values of a luminance signal corresponding to a plurality of pixels composing one screen;
a second temporary storage portion for storing digital values of color data representing three primary colors corresponding to the plurality of pixels composing one screen;
a luminance data extraction portion for extracting the digital values of the luminance signal from the digital video signal while the analog color video signal is a signal for a moving picture which is changed for each frame;
a read timing designation portion for designating timing at which the color data should be read from the digital video signal; a color data extraction portion for extracting for each color the digital values of the color data representing the three primary colors from the digital video signal at the timing designated by the read timing designation portion;
a write control portion for writing in a sequential order of frame scanning the digital values of the luminance signal for each frame which have been extracted by the luminance data extraction portion into the first temporary storage portion until the read timing is designated by the read timing designation portion, and writing the digital values of the color data which have been extracted for each color by the color data extraction portion into the second temporary storage portion when the read timing is designated by the read timing designation portion; and
a read control portion for sequentially reading out the digital values of the luminance signal for each frame which are stored in the first temporary storage portion and feeding the digital values to the display device, to display the moving picture corresponding to the analog color video signal in black and white, and sequentially reading out the digital values of the color data for each color in a frame which are stored in the second temporary storage portion and feeding the digital values to the display device, to display a still picture corresponding to the frame of the analog color video signal in colors.
As described in the foregoing, according to the first aspect, the analog color video signal is converted into the digital video signal, after which processing for accepting an image is digitally performed. Therefore, the circuit arrangement of the video signal digital processing device can be simplified, and the cost thereof can be reduced, as compared with a case where analog processing is performed as in the prior art. A part of digital processing can be easily replaced with program processing. Further, in the first aspect, the moving picture for reference is displayed in black and white, so that the amount of data to be processed can be significantly reduced, as compared with a case where it is displayed in colors. As a result, when processing in the part is realized by hard circuits, the scale of processing circuits can be simplified. Alternatively, when processing in the part is realized by software processing, the number of processing steps can be reduced, and the load on a CPU can be reduced.
A second aspect is an aspect dependent on the first aspect, which further comprises an input buffer memory for temporarily storing the digital values of the digital video signal, wherein the luminance data extraction portion extracts the digital values of the luminance signal out of the digital values stored in the input buffer memory, and the color data extraction portion extracts for each color the digital values of the color data representing the three primary colors out of the digital values stored in the input buffer memory.
A third aspect is an aspect dependent on the first aspect, wherein the read control portion sequentially reads out the digital values of the luminance signal for each frame which are stored in the first temporary storage portion to display the moving picture in black and white on a part of a display screen of the display portion, and sequentially reads out the digital values of the color data for each color in a frame which are stored in the second temporary storage portion to display the still picture in colors on the other part of the display screen of the display device.
As described in the foregoing, according to the third aspect, a black-and-white moving picture and a color still picture can be simultaneously displayed on the same screen.
A fourth aspect is an aspect dependent on the first aspect, wherein the read control portion performs in a time divisional manner a first read controlling operation for sequentially reading out the digital values of the luminance signal for each frame which are stored in the first temporary storage portion to display the moving picture in black and white on the display device and a second read controlling operation for sequentially reading out the digital values of the color data for each color in a frame which are stored in the second temporary storage portion to display the still picture in colors on the display device.
As described in the foregoing, according to the fourth aspect, a black-and-white moving picture and a color still picture can be displayed in a time divisional manner at different timings.
A fifth aspect is directed to an information storage medium, which is applied to a video signal digital processing device comprising an analog-to-digital conversion portion for converting an analog color video signal into a digital video signal, a first temporary storage portion for storing digital values of a luminance signal corresponding to a plurality of pixels composing one screen, a second temporary storage portion for storing a digital value of color data representing three primary colors corresponding to the plurality of pixels composing one screen, and an information processing portion and for digitally processing the color video signal and feeding the digitally processed color video signal to a display device, the information storage medium storing a program executed by the information processing portion,
wherein the program comprises:
a luminance data extraction program for extracting the digital values of the luminance signal from the digital video signal while the analog color video signal is a moving picture which is changed for each frame;
a read timing designation program for designating timing at which the color data should be read from the digital video signal; a color data extraction program for extracting for each color the digital values of the color data representing the three primary colors from the digital video signal at the read timing designated by the read timing designation program;
a first write program for writing in a sequential order of frame scanning the digital values of the luminance signal for each frame which have been extracted by processing based on the luminance data extraction program into the first temporary storage portion until the reading of the color data is designated by the read timing designation program;
a second write program for writing the digital values of the color data which have been extracted for each color by processing based on the color data extraction program into the second temporary storage portion when the read timing is designated by the read timing designation program;
a first read program for sequentially reading out the digital values of the luminance signal for each frame which are stored in the first temporary storage portion and feeding the digital values to the display device, to display the moving picture corresponding to the analog color video signal in black and white; and
a second read program for sequentially reading out the digital values of the color data for each color in a frame which are stored in the second temporary storage portion and feeding the digital values to the display portion, to display a still picture corresponding to the analog color video signal in colors.
A sixth aspect is directed to a video signal digital processing method of digitally processing a color video signal and feeding the digitally processed color video signal to a display device to display the color video signal thereon in a video signal digital processing device comprising an analog-to-digital conversion portion for converting an analog color video signal into a digital video signal, a first temporary storage portion for storing digital values of luminance signals corresponding to a plurality of pixels composing one screen, a second temporary storage portion for storing a digital value of color data representing three primary colors corresponding to the plurality of pixels composing one screen, and an information processing portion, which comprises:
the conversion step of converting the analog color video signal into a digital video signal by the analog-to-digital conversion portion;
the luminance-signal extraction step of extracting the digital values of the luminance signals from the digital video signal obtained by the conversion at the conversion step while the analog color video signal is a moving picture which is changed for each frame;
the timing-designation step of designating timing at which the color data should be read from the digital video signal; the color-data-extraction step of extracting for each color the digital values of the color data representing the three primary colors from the digital video signal at the timing designated at the timing-designation step;
the luminance-signal-writing step of writing in a sequential order of frame scanning the digital values of the luminance signals for each frame which have been extracted at the luminance-signal-extraction step into the first temporary storage portion until the reading of the color data is designated at the timing-designation step;
the color-data-writing step of writing the digital values of the color data which have been extracted for each color at the color-data-extraction step into the second temporary storage portion when the read timing is designated at the timing-designation step;
the moving-picture-displaying step of sequentially reading out the digital values of the luminance signals for each frame which are stored in the first temporary storage portion and feeding the digital values to the display portion, to display the moving picture corresponding to the analog color video signal in black and white; and
the still-picture-displaying step of sequentially reading out the digital values of the color data for each color in a frame which are stored in the second temporary storage portion and feeding the digital values to the display portion, to display a still picture corresponding to the analog color video signal in colors.